Antibiotic Regimen for Oxacillin-Sensitive Staphylococcus hemolyticus and Diphtheroids in LVAD Driveline Infection
For this oxacillin-sensitive staphylococcal driveline infection with diphtheroids, treat with nafcillin or oxacillin 12 g/24h IV divided every 4-6 hours plus rifampin 900 mg/24h divided every 8 hours for at least 4-6 weeks, given the device-related nature of this infection. 1
Primary Antibiotic Selection
Nafcillin or oxacillin is the drug of choice for oxacillin-sensitive staphylococci, superior to vancomycin for methicillin-susceptible infections 1, 2, 3
Add rifampin 900 mg daily (divided every 8 hours) as mandatory adjunctive therapy for device-related infections, as rifampin is essential for sterilizing biofilm on foreign bodies 1
Do NOT add gentamicin to this regimen—combination therapy with aminoglycosides is only indicated for prosthetic valve endocarditis, not driveline infections, and increases nephrotoxicity without improving outcomes 1, 2
Diphtheroid Coverage Considerations
Diphtheroids (Corynebacterium species) are typically contaminants in wound cultures, but heavy growth warrants consideration of true infection 1
The nafcillin/oxacillin plus rifampin regimen provides adequate coverage for most diphtheroids, as they are generally susceptible to beta-lactams 3
If cultures specifically identify Corynebacterium jeikeium (a resistant species), vancomycin would be required, but this is uncommon 1
Treatment Duration and Device Management
Minimum 4-6 weeks of IV antibiotics is required for device-related infections with documented bloodstream involvement or deep tissue infection 1
If infection is superficial driveline site only (erythema, drainage at exit site without deeper involvement), 2-3 weeks may suffice after surgical debridement 1, 4
Complete device removal is NOT routinely required for isolated driveline infections, unlike CIED lead infections—most driveline infections can be managed with antibiotics, local wound care, and surgical debridement if needed 1, 4, 5
Surgical driveline repositioning should be considered if antibiotic therapy fails (73% of patients require this intervention), with reinfection freedom of only 58% 5
Alternative Regimens
For true penicillin allergy (non-immediate type):
- Cefazolin 2 g IV every 8 hours plus rifampin 900 mg/24h divided every 8 hours 1
For immediate-type hypersensitivity to beta-lactams:
- Vancomycin (trough 10-20 μg/mL) plus rifampin 900 mg/24h divided every 8 hours 1
- Infuse vancomycin over 90-120 minutes to prevent red man syndrome 6
If vancomycin cannot be tolerated:
- Daptomycin 6 mg/kg IV daily plus rifampin (though daptomycin is FDA-approved for complicated skin infections at 4 mg/kg, device infections may require higher dosing) 7
Critical Monitoring Parameters
Obtain repeat wound cultures after 48-72 hours of therapy to document clearance and confirm no resistant organisms emerge 1
Monitor for persistent bacteremia—if blood cultures remain positive >24 hours despite appropriate antibiotics, device extraction becomes mandatory 1, 2
Assess for metastatic complications including endocarditis (obtain echocardiography), osteomyelitis, or deep abscess formation, which would require extended therapy 1
Daily sterile dressing changes with chlorhexidine application are essential adjunctive therapy 4, 5
Common Pitfalls to Avoid
Do not use vancomycin empirically when oxacillin-susceptibility is confirmed—beta-lactams are superior for MSSA 2, 3
Do not omit rifampin from the regimen for device-related infections—biofilm cannot be eradicated without it 1, 8
Do not delay surgical consultation if there is purulent drainage, abscess formation, or clinical deterioration despite 48-72 hours of appropriate antibiotics 1, 4, 5
Do not assume diphtheroids are always contaminants—heavy growth from deep tissue or repeated isolation suggests true infection requiring treatment 1